Acanthamoeba castellanii (Neff) encyst with the formation of a cellulose containing wall when placed in a starvation medium. It is proposed to continue studying several molecular events during this process. A soluble adenyl cyclase and phosphodiesterase have been examined in crude extracts and it is proposed to separate these activities in order to study these enzymes and their possible role during encystment. Previous work has indicated some role for cAMP in encystment. In addition the mechanism of cellulose synthesis of several beta-glucan by a particulate fraction of encysting cells. Various other enzymes which are related to the formation of glucosyl units for cellulose synthesis will be examined.